The present invention relates to a decoding signal error concealment system, and more particularly to a decoding signal error concealment system for correcting data which are determined as errors during the process of transforming coded image data into decoding signals in a digital VTR system.
Generally, to record image signals using a digital VTR system, the input image signal is transformed into a digital signal and is then input to the digital processing unit. The digital processing unit mentioned above transforms the time axis of the input digital signal, and compress the bit transfer rate to achieve high efficiency coding which decreases the number of bits of the image data information to be recorded.
By the above action, the image data having the compressed bit transfer rate is modulated for recording with the code for error correction added, and is then recorded on tape through the magnetic head.
Meanwhile, in order to reproduce the above image data recorded on tape, the data on the tape is read out by the head, and changed through detector to the data that existed before modulation, and is then input to the digital processing unit. The above digital processing unit corrects the data error due to burst error from damaged tape or random noise, and decodes the original image from the tape and transforms it into an analog signal.
The error concealment systems of conventional digital VTR systems which operate on the principles stated above, in the reaction between the data determined to be burst errors or errors due to random noise and the surrounding image element, the systems are designed to filter errors by applying the error data and a specified number of image elements as a block to a low pass filter. However, by coding a specified number of image elements as a block and recording that block on tape, the data determined as error affects the entire block containing the error data, during the playback of the data recorded on the tape and creates the problem of having the entire block processed as an error.